package main
import(
	"fmt";
	"strconv"
)

func AddUpper() func(int) (int,string){
	var n int = 10
	var str string = "prefix_"
	return func (x int) (int,string){
		n = n + x
		str += strconv.FormatInt(int64(x),10)
		return n,str
	}
}

func main(){
	f := AddUpper()
	a,b := f(2)
	a,b = f(3)
	a,b = f(4)
	fmt.Printf("%d %v",a,b)
}